/*
*	Sha1.h
*
*	Copyright (C) 1998
*	Paul E. Jones <paulej@acm.org>
*	All Rights Reserved.
*
*****************************************************************************
*	$Id: sha1.h,v 1.4 2001/03/20 06:25:06 paulej Exp $
*****************************************************************************
*
*	Description:
* 		This class implements the Secure Hashing Standard as defined
* 		in FIPS PUB 180-1 published April 17, 1995.
*
*		Many of the variable names in this class, especially the single
*		character names, were used because those were the names used
*		in the publication.
*
* 		Please read the file sha1.cpp for more information.
*
*/

#ifndef _SHA1_H_
#define _SHA1_H_

class SHA1
{

public:

	SHA1();
	virtual ~SHA1();

	/*
		*	Re-initialize the class
		*/
	void Reset();

	/*
		*	Returns the message digest
		*/
	bool Result(unsigned *message_digest_array);

	/*
		*	Provide input to SHA1
		*/
	void Input(	const unsigned char	*message_array,
	unsigned			length);
	void Input(	const char	*message_array,
	unsigned	length);
	void Input(unsigned char message_element);
	void Input(char message_element);
	SHA1& operator<<(const char *message_array);
	SHA1& operator<<(const unsigned char *message_array);
	SHA1& operator<<(const char message_element);
	SHA1& operator<<(const unsigned char message_element);

private:

	/*
		*	Process the next 512 bits of the message
		*/
	void ProcessMessageBlock();

	/*
		*	Pads the current message block to 512 bits
		*/
	void PadMessage();

	/*
		*	Performs a circular left shift operation
		*/
	inline unsigned CircularShift(int bits, unsigned word);

	unsigned H[5];						// Message digest buffers

	unsigned Length_Low;				// Message length in bits
	unsigned Length_High;				// Message length in bits

	unsigned char Message_Block[64];	// 512-bit message blocks
	int Message_Block_Index;			// Index into message block array

	bool Computed;						// Is the digest computed?
	bool Corrupted;						// Is the message digest corruped?
	
};

#endif
